Comparison of staphylococcus aureus nasal carriage by patients and healthcare workers in selected dialysis centers in Nairobi and neighbouring counties
Date of Award
Master of Medicine (MMed)
Dr Gunturu Revathi
Dr Geoffrey Omuse
Pathology (East Africa)
Background: Staphylococcus aureus (S. aureus) is a significant pathogen that causes both community and hospital acquired infections. The burden of S. aureus morbidity and mortality is disproportionately high in patients with end stage kidney disease undergoing dialysis. With the rising prevalence of non-communicable diseases leading to end stage renal disease and dialysis, the impact of S. aureus infections is projected to rise. Knowledge of nasal carriage of S. aureus and their antibiotic resistance profiles is essential in improving patient care through planning of infection prevention and control strategies as well as formulating appropriate empiric antibiotic guidelines. The aim of this study was to provide this knowledge.
Methods: The study was a prospective, multi-centre cross sectional study conducted in various dialysis centres in Nairobi and the surrounding counties of Machakos and Kiambu. Nasal swabs were taken from consenting patients and healthcare workers as well as information on recent antibiotic use, recent hospitalisation and duration of exposure. Nasal swabs were cultured at AKUHN within 8 hours and growth of S. aureus was determined through morphological and biochemical characteristics. Antimicrobial susceptibility testing was done thereafter through broth micro dilution technique on the VITEK-2® platform, (BioMérieux, France). A questionnaire assessing hand hygiene knowledge was also administered to consenting healthcare workers. Comparison of proportions between HCW and haemodialysis patients was done with the Chi-square test and antibiotic resistance patterns was analysed with percentages of susceptibilities tabulated.
Results: A total of 413 participants were enrolled into the study. This consisted of 141 healthcare workers and 272 patients. Nasal carriage of S. aureus was detected in 54(19.9%) patients and 26 (18.4%) healthcare workers. There was no statistical difference in nasal carriage rate between the two groups. Methicillin Resistant S. aureus (MRSA) was found in 9 (11.2% of all S. aureus) participants all of whom were patients. The mean score on the hand hygiene questionnaire was 50% among doctors, 52% among nurses and 49.5% among the other healthcare workers.
Discussion: The rate of S. aureus colonisation is comparable to local data but is lower than what is reported from other parts of Africa. The prevalence of MRSA nasal carriage was comparable to a previous local study in the healthcare worker group. MRSA nasal carriage in the patient group was lower than regional studies on the same population.
Conclusion: The carriage of MRSA isolates exclusively by patients in this study highlights the need for heightened infection prevention and control to prevent the spread in these high risk patients. Nevertheless, the relatively low MRSA carriage rate does not support the use of narrow spectrum antibiotics such as Vancomycin as empiric treatment for suspected S. aureus infections in dialysis patients in Nairobi and surrounding counties.